It took a while to get these to me because together with these leds I ordered some high CRI XP-G3's from Cutter as well and they halted the order because they did not have those on stock. After my request to separately send the 3bin 70 CRI ones, these arrived very quick by DHL.
The led tested is a Cree XP-G3 S5 3A, CRI=70. The partnr. is XPGDWT-01-0000-00ME3 . The package and invoice did not state which 3-bin this led is but the Cutter website says it is 3A. The appearance of the XP-G3 is clearly different from the XP-G2, it has no visible bond wires (probably it does not have any, like the Nichia and Luxeon leds), and like the other 'easy-white' leds from Cree, and many other leds from other companies, the phosfor layer is applied after attachment of the die on the led, so the complete surface of the led is covered with phosfor. This has its influence on the light emitting area: the edge is not as sharp as the XP-G2 die, and because the phosfor wraps around the edge of the die, the light emitting area is slightly larger. The phosfor is quite rough, and blue, yellow and red bits are visible, just like the latest production batches of the XP-G2 (the older XP-G2's had a much smoother phosfor with no distinct red bits). What is a very nice developement is that the XP-G3 will be available in 90CRI, even in many colour temperatures. I will receive some 5000K and 4000K ones, hopefully in early june.
XP-G3 S5 3A at 0.5mA current
The test was done like all my more recent emitter tests. I described it in detail in my XP-L test. , with two minor differences that should not matter significantly for the results: I used my Integrating sphere no. II instead of no. I, and for the current I used a clamp meter, which appears to measure 0.1A lower than the power supply current-reading that I used before.
In summary: 1) just one led was tested, reflowed on a DTP copper board (XP-Noctigon 16mm) 2) I used my large version II integrating sphere with high quality luxmeter, 3) the output numbers and voltages were measured with the led close to 'steady state' for each current, so warmed up and settled, you should be able to get these numbers in a well heatsinked flashlight. Mind that these are output numbers of the bare led, in a flashlight there will be losses from light obstructions, lens and optic, 4) output is in 'djozz-lumen' defined as 1/550 of the output of my Sunwayman D40A on high setting, which I hope is close to the real lumen, but at least is consistent over all my emitter tests done in integrating spheres.
Here is the result:
What can be seen in the graph:
*compared to the latest XP-G2 S4, the XP-G3 S5 has more output, but also the maximum is at higher current, which is consistent with the claim that it is a SC5-led which has a lower thermal thermal resistance (3 degC/W). It is clear that the thermal resistance is even better than the Nichia 219C (4.2 typ degC/W) and the Oslon Square (3.6 typ degC/W).
*I stopped the test at 10A, but it felt like the led could handle even a bit more current before blowing, that is probably thanks to the design without bond wires. After the test I lowered the current back to 5A and let it settle, the output had hardly suffered from the 10A treatment (minus 1.5%). This led is tough!
*the voltage is much lower than the XP-G2 (0.55V lower at 5A), it is almost as low as the Nichia 219C and the 3rd gen. Oslon Square. This is good for use in single li-ion flashlights. In fact my first test in a direct driven light with a Samsung 30Q gave 7.6A of current on a fresh battery. So unlike the XP-G2, you can drive this led at maximum output.
*the throw of the led (with dome) is comparable with a XP-L Hi led, so I included a XP-L Hi test too in the graph. Unfortunately in that test a bit of the led burnt at 5.5A which shows in the graph, but if you extrapolate the curve before the burning occurred you can see that a U5 bin of the XP-L Hi still is a better performer than the XP-G3 S5. And the top-bin V2 of the XP-L Hi will even put out more light. So depending on the application, the XP-L Hi may still be the better choice (reflector thrower) but for small triples and quads with Carclo optics, the XP-G3 will give a much nicer beam!
How about dedoming this led that is build quite different than the XP-G2 ? Some first attempts by other BLF-members at hot dedoming or in gas were not promising. My own (limited skills !) first attempt at a sliced dome produced a working led but the throw was disappointing. See here. So for now, the 'king of throw' is still the 'old type' XP-G2 S4 2B, which unfortunately is not available anymore.
The XP-G3 is a major improved led compared to the XP-G2 and has also better output performance than the top 3535-size leds from the other manufacturers, and that with a comparable low voltage, so it can easily be driven at its maximum output. I did not do an attempt yet to compare the tint of this S5 3A led with other leds, but my first impression is that the tint is a very nice true white, even my sliced emitter has a good neutral white tint. The led seems to handle immense abuse which is good for hard driven hot lights (triples and quads come to mind). If the led can be succesfully dedomed after all (or if a HI version becomes available) it will be the top thrower led but with dome it has the competition of the XP-L Hi that is (at twice the price!) still the better performer. The 90 CRI variants will probably become very popular as the best performing high CRI leds around.
Thanks for reading!